Dual hydraulic swivel joint



NOV. 17, 1953 MccLAlN 2,659,615

DUAL HYDRAULIC SWIVEL JOINTS Filed June 21, 1949 2 Sheets-Sheet l 40 E G u Is I INVENTOR.

THOMAS H. MCCLAIN Agent Patented Nov. 17, 1953 DUAL HYDRAULKC SWIVEHJ. JOINT lihomas H. McClain, Altadena, Calif., assignor to Lockheed Aircraft Corporation, Burbank, Calif.

Application June 21, 1949, Serial No. 100,435

1 Claim. 1

This invention relatesto hydraulic swivel or swing joints adapted to carry pressure fluids to and from a movable or telescoping mechanism, either as supply and return lines, as, for example, to a hydraulic motor or a double acting hydraulic cylinder; or. as dual lines to separate hydraulic mechanisms;

In providing high pressure hydraulic lines to relatively movable parts or mechanisms it has heretofore been the practice to use flexible hoses, telescoping or trombone tube connections, or swivel joint with or without nut-cracker or scissors linkage. Heretofore, each connection had to be set up separately and. independently so that parallel lines, as for supply and return connections or dual functions, required independent duplication of fittings and swivels, joints, or the like. By way of example; without restricting the present invention thereto, a retractable airplane landing gear having a telescoping shock strut and dual brakes would require two separate hydraulic lines each having one set of swivel joints at the strut pivot point and another set of swivel joints and scissors connections at the telescoping part of the strut. The present invention relates to combining the two. separate connections or linkages into a dual linkage simultaneously providing two separate hydraulic lines in the space normally required by a single line, and capable of large rotational and/or translational movements.

It is accordingly an object of this invention to provide an improved swivel or swing joint arranged to provide dual hydraulic circuits which provide fluid to double actin or dual hydraulic mechanism movable rotationally and/or translationally relative to the source or" hydraulic fluid and/or controls therefor.

It is a further object of this invention to provide a dual passaged device of the type described that can be used singly as a swivel or swing joint or in multiple or series to provide a nut-cracker or scissors effect to absorb misalignment or relative movements without change in the volume of the fluid contained'therein.

It is also an object of this invention to provide a dual swing joint of the type described that will be in substantial hydraulic balance regardless of variations in hydraulic pressure between the dualhydraulic conduits.

It is still a further object of this invention to provide a compact dual swing joint of the type described capable of carrying high hydraulic pressuresin theorder. of 3000 pounds to the square inch;

Other and further. objects of I my inventionwill appear. as"v the detaileddescription thereof pro.- ceeds; a specific embodiment being disclosed in the accompanying drawings wherein:

Figure 1 shows a dual scissors or nut-cracker 2 linkage including the swing orswivel joints of my invention;

Figure 2 is an enlarged view, partly in section, showing one of the joint members of Figure 1; and

Figures 3 and 4 are'seotions, in planesat right angles to each other, of two joint members, such asshown in Figure 2, mounted: on a common barrel.

As shown on the drawings, a scissorsor nutcracker arrangement of a plurality of swing or swivel joints is intended to carry dual hydraulic pressure lines from one location I6 to another location I I, where relative motion is expected between the two locations. lting the invention thereto, include reciprocating, traversing, oscillating, or other types of regular or irregular motion of either location respective to the other; such as a reciprocating working table of a machine tool, or a telescoping shock strut for airplane landing gears.

In Figure 1, either side may be-considered the relatively movable one, and for convenience'in what follows the left hand mounting Or location It will be considered the fixed side, having a pair of hydraulic lines I2 and I3 leading thereto. Accordingly, the right hand side'or location II will be considered the movable one, asecond pair of hydraulic lines I l and I5 leading therefrom to either a double acting hydraulic mechanism (not shown) wherein the lines I4 and l5become supply and return lines; or to separate or dual mechanisms under separate control wherein back flow through the same lines provides for return of the mechanisms, as commonly used in hydraulic brake control lines, for example.

Each of the three pairs of housing members I5 and Il shown in Figure l are identicalbe tween the pairs of members pivoted on a common barrel !8, but alternate pairs are of opposite- Accordingly, the two pairsof members Ifi' hand. adjacent to the locations I9 and II are identical, and the upper pair of members I 'I forming the scissors joint are of opposite hand. Although Figure'Z shows. the front member I6 of the left hand pair; as rotated into a horizontal direction, the detailed description will apply to both members lfi -and I7 as the only diiference is the angular position of the pairs of tubes. '9 and 29 connectingthe two pairs of'members I 6' and Il forming the pairs of scissors linkages.

Referringnow toFigures 3 and l, each hous ingmember I5 is of somewhat block-life form' having a central bore 2|. Two of these members are'mounted side by side on'the pivotbarrel I8 andvare retained thereon'by cover plates 22.

Spaced annular grooves 23 and 24" are; cut' into? the wall of the bore El and are intersected by parallel holes 25 and 25 on opposite sides of the bore 2! for the connecting tubes such as I9 and Examples, without lim- 23 which may be attached as by brazing 21 or with conventiona1 tube couplings 28. The opposite disposition of the holes 25 and 26 and their corresponding tubes marks the difference between the members I6 and I1; if member I6 is as shown in the detail figures members I'I would have the holes transposed to the opposite corners, where lightening and/or mounting holes 29 are shown in Figure 3.

The barrels I8 for both members I6 and I! are identical, two members I6 or IT, as the case may be, being mounted side by side on a barrel for independent rotation thereon. Grooves 3B are turned into the barrel to align with the grooves 23 and 24 in the wall of the bore 2| in the member I6 or IT. Suitable seals are mounted in grooves 3| outside of and between the grooves 30, these seals for high pressure service preferably comprising rubber-like rings 32 with leather back-up rings 33 on one or both sides according to the direction of the pressure. The barrel has a pair of longitudinal holes 34 bored from one end and of sufiicient depth to extend from the groove 23 in one member I6 to the corresponding groove in the other member I6 (Figure 3) and the open ends of these bores are sealed by plugs 35. The opposite end of the barrel is drilled and tapped for cap screws 36 which retain the cover plate 22 in place. Longitudinal holes 31, similar to the holes 34, are bored from the opposite end of the barrel in a plane at right angles to the plane of the holes 34 (see Figure 4) to connect the corresponding grooves 24 in the two members IS, the open ends being plugged and covered by a second plate 22 as previously described. The pairs of bores 34 and 31 are interconnected by cross bores 34 and 3'! to facilitate flow.

The two scissors links formed by the tubes I9 and 29 have a member I6 at one end and a member H at the other or joint pivot. These links can be assembled either way, the only requirement being that the two members IE or I! mounted on a common barrel must match. I have chosen to show the members I6 as at the fixed and moving locations ID and II with the rearward member I6 fixed to structure at said locations. The mountings for this purpose may form a bracket 33 as shown at the left in Figure 1, where the member I6 is mounted on the bracket by bolts 39 through the lightening holes 29. Alternately, a bracket 46, as shown at the right of Figure 1, may overlie or replace one or more cover plates 22 and support the rear member I6 by means of the cap screws 36. With this latter mounting the barrel is held stationary and both members I6 can swivel thereon, so that the rear member I6 can be turned to best suit the desired layout of the tubes I4 and I coupled thereto. While it is convenient to use member I6 to receive the supply and/or return tubes I2, I3, I4 and I5, it will be evident that these members can be specially formed to facilitate their mounting to the associated structure.

In the operation of the device of my invention, it will be assumed that the hydraulic lines I2 and I3 are respectively supply and return lines for some operating device connected to the lines I4 and I5. High pressure fluid from the line I2 enters the rear member I6 (Figure 4) through the bore 26 and thence into the groove 24 in the member I6 and thence into the mating groove in the barrel I8 whence it passes into the two axial bores 31 in the barrel and out of the corresponding bore 26 into the tube 26 to the upper or intermediate scissors pivot in Figure l, where the flow through the two members I1 is substantially the same. Fluid leaves the front member I! through a second tube 26 and thence through the pair of members I6 at the location I I, emerging through the line I4.

Return flow through the line I5 enters the member I6 (Figure 3) through the bore 25 and enters the groove 23, barre1 groove 38 and axial bores 34 to exit through the adjacent member I5, then the right hand tube I9 to the scissors joint member I! and the left hand tube I9 to the left hand pairs of members I6 at the location Ill and thence out the tube I3 to the control valve or hydraulic reservoir.

It is to be noted that the two hydraulic circuits just described are maintained separate and independent throughout the mechanical movements of the several parts, so that the separate circuits may be used for either supply and return circuits, for reversible drives, or for parallel or independent operation of separate or dual mechanisms, as for example dual hydraulic brake systerns.

Having thus described my invention and the present preferred embodiments thereof, I desire to emphasize the fact that many modifications may be resorted to in a manner limited only by a just interpretation of the following claim.

I claim as my invention:

A swing joint comprising a cylindrical barrel having at least two bores parallel to the axis thereof and extending from opposite ends of said barrel and each terminating short of the other end of said barrel with four separate spaced annular grooves in the surface of the barrel, alternate grooves communicating with one of said bores and the remaining grooves communicatin with the other of said bores, a pair of identical housing members embracing the cylindrical surrace of said barrel in side by side relationship for separate rotation thereon, each member having a pair of separate internal annular grooves in alignment with and communicating with an adjacent pair of the grooves in the surface of said barrel, separate parallel passageways on each or" said members at substantially right angles to the barrel axis and opening on a common face diagonally disposed on either side of said barrel in tangential communication with the separate grooves in said members to provide fluid connections, sealing plugs inserted into the open ends of said bores, end plates attached to said barrel to retain said sealing plugs in position, and sealing means carried by said barrel on each side of each of said grooves to form separate conduits passing from one housing member through the barrel and thence out through the other of said housing member.

THOMAS H. MCCLAIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,343,491 Bard Mar. '7, 1944 2,372,721 Harcourt Apr. 3, 1945 2,434,629 Taylor Jan. 13, 1948 2,481,404 Donner Sept. 6, 1949 

